Cylinder liner securing apparatus

ABSTRACT

A device for securing a cylinder liner (3) to a respective pumping module (2) in a reciprocating pump has a set of arrangements each with a hydraulically activated piston (8), a rod (11) of which is adapted to receive a nut (12), the retraction of which forcibly compels in attraction the cylinder liner (3) and the pumping module (2).

This invention is in the field of reciprocating pumps and particularlyrelates to a means for aligning and securing the cylinder liners of suchpumps to their respective pumping modules. The means is also adapted toenergise the seals of such liners.

Reciprocating pumps are well-known and a particular example discussed inthe present specification is oil-field mud pumps. The invention is not,however, limited to mud pumps but finds application in a variety ofreciprocating or positive displacement pumps.

In the past, there have been several different types of ways to attachcylinder liners to their respective pumping modules and these may varyaccording to make of pump in which they are used. One embodimentpresently known employs a tapered concentric clamp, whale another uses aconcentric screw clamping arrangement.

It is important that the means for aligning and securing the cylinderliners may be implemented without undue effort and down-time. Cylinderliners are required to be changed frequently and this causesconsiderable inconvenience if the means and method for releasing the oldcylinder liners and fitting the replacement cylinder liners are slow ordifficult to operate. It has been found that existing systems or meansfor securing cylinder liners to respective pumping modules have beendifficult to operate for a plurality of reasons, including theinvolvement of heavy components, the handling of which may be dangerousfor operators. These systems also require considerable strength, skilland reliability of operators, together with the use of heavy tools inconfined spaces. Yet further, the securing force is dependent on theextent of wear and the general condition of a plurality of the securingcomponents.

According to the invention, there is provided a means for securingcylinder liners to pumping modules in reciprocating pumps, wherein saidmeans includes a plurality of arrangements having a piston slidablewithin an hydraulic cylinder, said pistons having a rod adapted toreceive a nut, said rods extending outwith their respective cylindersand being passed through respective apertures in a member adapted togrip said cylinder liner, wherein retraction of said piston and nutcauses said member to forcibly compel said cylinder liner towards saidpumping module.

Preferably, said arrangements are fastened to said pumping module.Preferably, said arrangements also include a spring or springs forlocation between the top of said cylinder and the piston. Hydraulicfluid can be inserted between the piston and the cylinder base by anexternal pressure source.

Preferably, there are four or more said arrangements spaced at intervalsabout and externally of the circumference of the cylinder liner.

Preferably, said means further includes non-rotational apparatus forpreventing rotation of said pistons within said cylinders, wherein saidnon-rotational apparatus preferably includes one or more dowel rodswhich extend between said pistons and said cylinder base.

Preferably said member comprises a clamping ring having correspondingapertures for receiving said piston rods.

An example embodiment of the invention will now be described by wayexample only, with reference to the accompanying Figures, in which:

FIG. 1 is a sectional view of a cylinder liner and pump moduleincorporating the invention; and

FIG. 2 is an end view of the securing means illustrated in FIG. 1.

A reciprocating pump generally described at 1 comprises a module 2 andcylinder liner 3. It is desirable that the cylinder liner 3 is securelyheld up against the face 4 of the module 2. Between the cylinder liner 3and the module 2 there is-provided a seal 5 which, in its unenergized(i.e., uncompressed) state, usually requires to be compressed by thecylinder liner 3, thereby a gap is created between the adjacent faces ofthe module 2 and cylinder liner 3.

In order to prevent the existence of this gap, it is necessary toforcibly push the cylinder liner 3 against the module 2 and this isachieved by securing means, generally described at 6. The effect ofcompressing the cylinder liner 3 against the face 4 of the module 2 isto energise or compress the seal 5. This compression is of coursedesirable to increase the effectiveness and efficiency of the seal 5.The securing means 6 comprises a plurality of assemblies 20, whereineach assembly includes a cylinder 7 adapted to house a slidable piston8, a plug 9 and clamping springs 10. The piston 8 is further providedwith a rod 11 which extends outwith the cylinder 7. The rod 11 isprovided with a threaded portion 21 adapted to receive the nut 12.Furthermore, the rod 11 passes through the shoulder or clamping ring 13which circumnavigates the cylinder liner 3 and is pressed up against thelug 14 on the cylinder liner 3. In a preferable embodiment of theinvention, there is provided one or more dowels 15 which engage bothpiston end plug in each arrangement for the purpose of preventingrotation of the piston.

In the embodiment shown, the securing means 6 includes four or morearrangements 20 having the aforesaid components 7, 8, 9, 10, 11, 12.These arrangements 20 are permanently bolted by the bolts 22 to themodule 2, although the nuts 12 are detachable, thereby allowing removalof the cylinder liner 3.

In use, when a cylinder liner 3 is positioned against or nearly againstthe module 2, the shoulder or clamping ring 13 is then fitted over eachof the piston rods 11. The nuts 12 are then threadably applied to therods 11. The method of forcibly securing the cylinder liner 3 to thepumping module 2 is then implemented. This involves inserting hydraulicfluid 25 between the piston head 8 and the cylinder base, such that thepiston is extended to a greater extent outwith the cylinder 7 and thenut 12 is given freedom to be tightened by further rotation along thepiston rod 11 towards the clamping ring 13. Preferably, this process isperformed with all of the securing arrangements 20 simultaneously. Itshould be noted that the apparatus and method described herein allowsthe nuts 12 to be tightened by hand. It will be appreciated that this isa considerable advantage over the requirement of using heavy tools whichhas been the practice in the past.

The invention thus provides components which are considerably lighterthan comparative components used heretobefore. In view of it negatingthe requirement of heavy tooling or handling, the components are lesslikely to be damaged during the removal or securing of cylinder linersand thus the invention permits greater repeatability and reliability.Furthermore, the need for intensive manual or skilled labour byoperators is also mitigated. Similarly, there is a reduced danger ofinjury to operators or by-standers during such operational andmaintenance functions.

A further advantage of the invention is that the clamping pressure maybe predetermined by the springs and it is possible to achieve uniformpressure around the periphery of the liner, which enables perfect lineralignment.

Other advantages of the invention will become apparent to operators andassociated personnel involved in the implementation and operation of theinvention, including the fact that reduced time is required to affectthe replacement of a cylinder liner.

Further modifications and improvements may be incorporated withoutdeparting from the spirit or scope of the invention.

We claim:
 1. An apparatus for securing a cylinder liner to a pumpingmodule in a reciprocating pump, said apparatus comprising a plurality ofarrangements each having a piston slidable within a hydraulic cylinder,said piston having a rod adapted to receive a nut, said rod extendingbeyond its respective cylinder and being passed through a respectiveaperture in a member adapted to grip said cylinder liner, whereinretraction of said piston and nut causes said member to forcibly compelsaid cylinder liner towards said pumping module.
 2. An apparatus asclaimed in claim 1 wherein the said plurality of arrangements arefastened to said pumping module.
 3. An apparatus as claimed in claim 1wherein said plurality of arrangements each include at least one springlocated between the top of said cylinder and the piston.
 4. An apparatusas claimed in claim 1 wherein the piston and the cylinder base define aspace for accommodating hydraulic fluid.
 5. An apparatus as claimed inclaim 1 wherein said plurality of arrangement comprise at least fourarrangements spaced at intervals about and externally of thecircumference of the cylinder liner.
 6. An apparatus as claimed in claim1 further including non-rotational means for preventing rotation of saidpiston within said cylinder, wherein said non-rotational means includesat least one dowel rod which extends between said piston and saidcylinder base.
 7. An apparatus as claimed in claim 1 wherein said membercomprises a clamping ring having said aperture for receiving said rod.